Credit: X-ray: NASA/CXC/CfA/J.Grindlay & C.Heinke; Optical: ESO/Danish 1.54-m/W.Keel et al.
Turn Turn Turn
Pulsars are ultradense neutron stars that spin very rapidly, sometimes many times a second. Milli-second pulsars are those with spin periods of a few thousandths of a second (meaning that the star makes a few hundred, up to one thousand, revolutions each second). It strains the imagination to understand how such a massive object could be spun up so much. A new observation of the globular cluster 47 Tuc by the Chandra X-ray Observatory has helped astronomers better understand the process by which milli-second pulsars are formed. Globular clusters like 47 Tuc consist of many thousands (or even millions) of stars packed into a space only a few light-years across. Globular clusters are very crowded: generally, in the centers of globulars, stars are only about 0.1 light years apart. This means that the chances for stellar interactions are high. Astronomers believe that if a normal star comes close enough to a neutron star in the cluster center, the neutron star may pull mass from the companion star, and this accretion can help spin up the neutron star to milli-second pulsar rotations. The Chandra observation of a millisecond pulsar called 47 Tuc W (shown above right) shows that the star is similar to an X-ray binary system, which helps confirm the spin-up scenario.
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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:20:51 EDT